Background
Paratuberculosis, or Johne's disease, is an infectious bacterial disease in animals that is caused by Mycobacterium avium subsp. paratuberculosis (MAP). Johne's disease has been spreading slowly through domestic livestock populations for nearly a century and has become endemic in many countries. MAP, the etiologic agent of Johne's disease, is being investigated as a pathogen of animals that may be naturally transmitted to humans. In the U.S., dairy cattle represent the largest population of MAP-infected animals (Johne's disease positive herds), and therefore the most likely source of direct or indirect exposure to humans.

MAP, like other members of the Mycobacterium avium complex is an opportunistic pathogen in immune compromised persons. The question remains whether generally immunocompetent individuals can be infected with MAP and whether this leads to disease. Leaving aside whether or not MAP is a pathogen to humans, there are several possible modes of transmission, including exposure to a contaminated environment (soil, water), person-to-person horizontal transmission, direct contact with infected animals, pre-harvest and post-harvest contamination of foods including produce and food products originating primarily from dairy cattle, but also from beef cattle, sheep, and goats. Specifically, the presence of MAP in raw milk has raised concerns about whether MAP has potential public health significance.

Charge to the Subcommittee
The Committee is asked to limit their deliberations to the consideration of a very specific set of questions. The Committee is not being asked to consider the question of whether or not MAP is a human pathogen.

The Committee is asked to consider the following questions during their deliberations:

What food, water, or environmental sources are of most concern with respect to exposure of humans to MAP?

What are the frequencies and levels of MAP contamination found in the above referenced sources?

What is the efficacy of the current methods of detection for MAP?

What processing interventions are available for the foods of concern to eliminate or reduce the levels of MAP contamination to an acceptable level or to ensure that MAP does not enter the food supply?

What are the research needs to determine:

additional sources of MAP;

the frequencies and levels of MAP contamination in specific sources of concern;

potential processing interventions to eliminate or reduce the levels of MAP contamination; and